Review pricing formulas for all 22 models against actual provider rates #210

Context

The dynamic pricing system (PR #209) added ProviderPricing formulas to all 22 model definitions. During implementation, we already found one inaccuracy — Kling's formula ignored the generate_audio flag ($0.112/sec vs $0.14/sec), which was fixed in 37b3875.

There may be similar issues with other models. Each formula should be verified against the current provider pricing page.

What needs to be done

For each model definition in src/definitions/models/*.ts, verify:

1. Rate accuracy — does the per-unit cost match the provider's current pricing?
2. Parameter coverage — are all price-affecting parameters accounted for? (e.g. resolution tiers, audio toggles, model variants)
3. Bounds correctness — do minUsd and maxUsd reflect the actual min/max possible costs?
4. Description clarity — does the description string accurately describe the pricing without mentioning features that aren't modeled?

Models to review

Known gaps

• Some models have multiple provider variants with different pricing tiers (e.g. Kling v2, v2.5, v2.6, v3, O3 all map to the same formula). These may actually have different per-second rates.
• The gateway maps ~50 model IDs to SDK model definitions in gateway/src/services/pricing/dynamic.ts. If provider rates differ per variant, we may need per-variant pricing in the SDK.
• HeyGen pricing uses an estimated $0.10/sec and speech-rate heuristic (12.5 chars/sec) — needs verification against actual HeyGen invoices.

Related

• SDK PR: feat: provider cost formulas and render pricing callback #209
• Gateway PR: vargHQ/gateway#101
• Render PR: vargHQ/render#72